Telling the Truth
by Embolalia
Summary: The story of how Ziva David learned to lie to a polygraph machine. spin off from Conversations chapter 92


**Telling the truth**

This story comes from chapters 86 and 92 of my series Conversations, in which Ziva tells Gibbs the story of how she learned to pass a polygraph. It's just a reference there and I enjoyed coming up with the story, so here you have the whole thing. This is set when Ziva is finishing her army years and transitioning to Mossad, so I'll put her age at about 20.

I did do a bit of research into polygraph testing before writing this, by which I mean that I read the wikipedia entry on polygraphs. So there is a little truth to this, but I have not actual knowledge of how this all works.

* * *

"Ready?" Ari grinned eagerly, raising his eyebrows as if to dare her.

"Absolutely," Ziva answered defiantly, spinning the chair opposite him. She sat down backwards, resting her arms on the back of the chair.

"Keep your eye on the monitor," he reminded her.

Ziva nodded, then snatched up the list of questions. "Is your name Ari Haswari?"

"Yes," he answered smoothly.

She glanced over the readout, then went on. "Do you have any aliases?"

"Nope," Ari answered, grinning.

Ziva nodded. Two right so far. "Is Tali David your sister?"

"No," he said firmly, an affable smile still on his face.

She looked back at the monitor. She knew he was lying—they were here so he could train her to do it—but seeing his answer come up true, Ziva couldn't help the chill that passed over her. Her eyes flickered back to Ari. "Is Tali David your sister?" she asked again.

This time he nodded. "Yes."

Ziva relaxed. To her surprise the answers were indifferentiable. Her gaze rested on Ari for a long moment. She now knew better than to trust lie detector tests. It was only later she would find she should have learned better than to trust _him_.

Ari took her silence for impatience with practicing administration. "Ready for some pointers?" he asked lightly. "Then you can take a turn. You only have a week until you do your security clearance test for Mossad."

She frowned at him, began to untape the wires from his arms. "I don't need to lie to Mossad, Ari. What could they ask me that I don't want them to know?"

He smiled gently, removed the last of the tape himself with a wince. "You never know, Ziva."

She gave him a skeptical look, sure he was trying to tease her. "Well, I do plan to lie to the intelligence agencies of certain foreign countries if I'm ever taken, so go ahead, explain to me what to do."

Ari nodded. "Alright, then. The test is measuring changes in your blood pressure, sweat level—physical reactions that usually accompany stress."

"Like lying," Ziva answered, slightly impatient. "I know."

He grinned at his impetuous little sister. "The trick is learning to control your physical responses, your heart rate, your breathing, that sort of thing." Ari slipped easily into instruction mode, the voice and persona he wore regularly working with the Mossad trainees a year and two years ahead of Ziva. As he stepped in to the authoritative role, he noted how his sister fell quickly into her military training: alert and silent. She would serve their father unquestioningly, he thought with a heavy heart. If only she had stayed a bright-eyed child forever.

A half-hour later, Ari wrapped up his instruction and Ziva clapped in delight as he strapped her into the polygraph machine.

He smiled at her. "Is your name Ziva David?"

"Yes," she answered excitedly.

"Are you joining the Mossad to serve Israel?"

"Yes." Another confident answer.

He couldn't keep a mischievous grin off his face as he read the next question from the list he'd prepared. "Are you sleeping with Saul Stein?"

"Ari!" Ziva shouted, outraged. "No fair!"

"That's what we call an _emotional reaction_," Ari teased, laughing.

She crossed her arms, glaring at him.

"Are you?" He was glad to see her dismiss the context of the question and take a deep, steadying breath.

"No," she said calmly.

Ari glanced at the readout and scoffed. "Oof. You totally just lied."

"Let me see!" she protested, but Ari shook his head.

"Let's try again." He laid out the strategies for her again, glad to note that this time she was not simply at attention but instead intently focused.

Nearly an hour later he picked up his list for the fourth time."Don't forget," he began patiently.

"Stress over the controls, relax over the contradictions," she finished smoothly. "You don't have to keep saying, I just have to get it to work."

A noise at the door suddenly drew both their attention.

"Children?"

They froze as Eli David appeared in the doorway.

"Hello, Abba," Ziva said quickly. Ari nodded his own greeting.

"What is this?" their father asked pleasantly.

They both knew well the threat that could lurk behind his pleasant tones. "I was helping Ziva get familiar with the polygraph process," Ari said smoothly. "I knew a girl I trained with who was thrown out simply because she was so terribly stressed out that she bungled the lie detector."

Eli looked back and forth between them. "It is good to see you together," he said, with a fondness that seemed suddenly real. "Let me help." He held out his hand for the sheet of questions.

Ziva began to gasp in protest, then caught Ari's frantic glance of reassurance. She took a deep breath. _Control your emotional reactions_, she reminded herself.

Their father came over and reviewed the settings on the polygraph with the quickness of long familiarity, tweaking a few dials as he looked. Then he turned sharply to his oldest daughter. He glanced down at the paper he was still holding. "Is your name Ziva David?"

"Yes," she answered at once.

"Are you joining the Mossad to serve Israel?" He raised an eyebrow with a proud smile.

"Yes," Ziva said, smiling back.

Eli looked down and frowned.

Ziva's stomach dropped, her eyes widening as she looked to Ari for help. He looked unsettled too, but merely shook his head. She swallowed hard.

"Are you sleeping with Saul Stein?" Eli intoned, watching her carefully.

"No." Ziva shook her head firmly.

He glanced at the machine and nodded, then looked to Ari. "She is not," he said pointedly. "Next time perhaps you should keep your friends away from her if you do not want to worry they might seduce her."

Ari nodded firmly, resisting glaring at Ziva, who was grinning at him from behind Eli's back. "I'll keep them far away, sir," he said darkly.

Ziva straightened her face before her father could turn. She sighed. Now that that hurdle was past, she was confident she could pull this off. She relaxed and answered the next half dozen questions with ease.

They had just exhausted the questions Ari had already asked her when suddenly Eli stopped, fixated on the next query. Ziva's eyes darted to Ari, who was studying their father, an odd look in his eyes.

Eli looked up at her, intensely. "Do you love your father?"

She swallowed. Why was her heart suddenly pounding just as if she were answering the question about Saul? She deliberately slowed her heart rate as Ari had instructed. "Yes," she said sweetly, pasting a smile on her face.

Her father glanced at the machine, hmphed, nodded his satisfaction.

Ziva betrayed no sign of her relief, but when she glanced away from her father, she could see that Ari had now turned his curious look on her. She met his eyes frankly, trying to show him her pleasure that his lessons had worked.

Eli nodded in satisfaction and folded the paper up. "You hardly seem too stressed to pass," he said with approbation. "Put this machine away, Ari."

"Yes, sir." Ari began to disengage his sister at once.

"And wash up," their father said as he left the room, "It's nearly time for dinner."

As the door closed him him Ziva collapsed against her chair, exaggerating her relief. "I can't believe I did it!" she hissed.

Ari nodded, his face pensive. "You're a quick learner."

Ziva smiled, then flinched, looking down for a moment. "Are you pissed about Saul?" she asked nervously.

Her brother hesitated. "He didn't pressure you into anything?"

"Of course not!" she protested.

He shrugged, shaking his head with exaggerated misery. "Then I guess it's fine."

Ziva grinned, reached out as he set the electrodes down to hug him. "Thanks, Ari," she said quickly.

He hugged her back for a moment, then released her. "Go wash up," he repeated. "I'll put this away."

She nodded and raced off, full of the success of her afternoon.

XXX

Telling the story years later, Ziva would remember how at the time she'd assumed Ari understood her smile, had known it was meant for him, not Eli. In retrospect she would wonder what the question had meant, why he'd included it, and how much differently their relationship would have gone if he'd asked her about her allegiance to Eli before he taught her to lie. But by the time she told the story to Gibbs it was too late to ask Ari any of those questions, or any of the thousand others she'd learned she should have asked.

It was Gibbs who pointed out the obvious, the question that chilled her to the core: if people could be as accurate as lie detectors, did Eli, a man who had conducted thousands of interrogations, know when she lied? Had she become disposable that long ago? He was still alive to ask, at least, but Ziva knew she never would. The answer didn't really matter anymore-and she'd never believe he was telling the truth anyway.


End file.
